%  for  math books
%  Uses package amsthm
%   only uses chapter number, no section number

% NUMBERED ENVIRONMENTS

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[chapter]
\newtheorem{theorem}[thm]{Theorem}
\newtheorem{lemma}[thm]{Lemma}
\newtheorem{cor}[thm]{Corollary}
\newtheorem{corollary}[thm]{Corollary}
\newtheorem{prop}[thm]{Proposition}
\newtheorem{proposition}[thm]{Proposition}
\newtheorem{conj}[thm]{Conjecture}
\newtheorem{conjecture}[thm]{Conjecture}

\theoremstyle{definition}
\newtheorem{example}{Example}[chapter]
\newtheorem{examples}[example]{Examples}
\newtheorem{definition}{Definition}[chapter]
\newtheorem{defin}[definition]{Definition}
\newtheorem{problem}{Problem}[chapter]
\newtheorem{prob}[problem]{Problem}
\newtheorem{note}{Note}[chapter]

\newcommand{\epigraph}[3]
{\vspace{2ex}\begin{quote}\small
   {#1} \vspace{0.3ex}\\
{\bf{---#2}$\;$}{#3}
    \end{quote}
}